import sys
import pygame
from bullet import Bullet

def check_keydown_events(event,ai_settings,screen,ship,bullets):
    if event.key == pygame.K_RIGHT:
        ship.moving_right=True
    elif event.key == pygame.K_LEFT:
        ship.moving_left=True
        
    elif event.key == pygame.K_SPACE:
        #设置子弹限制
        if len(bullets)< ai_settings.bullets_allowed:
            new_bullet = Bullet(ai_settings,screen,ship)
            bullets.add(new_bullet)
        
def check_keyup_events(event,ai_settings,screen,ship,bullets):
    if event.key == pygame.K_RIGHT:
        ship.moving_right = False
    elif event.key == pygame.K_LEFT:
        ship.moving_left = False

    
def check_events(ai_settings,screen,ship,bullets):
    #响应按键和鼠标事件
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()     
        elif event.type == pygame.KEYDOWN:
            check_keydown_events(event,ai_settings,screen,ship,bullets)
        elif event.type == pygame.KEYUP:
            check_keyup_events(event,ai_settings,screen,ship,bullets)

        

def update_screen(ai_settings,screen,ship,bullets):
    # 每次循环时都重绘屏幕
    screen.fill(ai_settings.bg_color)
    for bullet in bullets.sprites():
        bullet.draw_bullet()
    ship.blitme()
    # 让最近绘制的屏幕可见
    pygame.display.flip()

def update_bullets(bullets):
    bullets.update()
    for bullet in bullets.copy():
        if bullet.rect.bottom<=0:
            bullets.remove(bullet)

                
